Abstract: ob＜x＞jective To explore the value of application of bronchoalveolar lavage during Sub-emergency cardiopulmonary bypass (CPB) surgery for infants with congenital heart disease (CHD) complicated with severe pneumonia. Methods From December 2016 to December 2019, 25 cases of infants with congenital heart disease complicated with severe pneumonia were performed in our hospital. They were randomly divided into an observation group (12 cases) and a control group (13 cases). The observation group was given bronchopulmonary lavage after the establishment of CPB. The time of postoperative ventilator-assisted ventilation, stay time in the intensive care unit (ICU), Clinical pulmonary infection score (CPIS) and postoperative complications were compared between the two groups. Results All 25 patients were cure. The postoperative ventilator-assisted ventilation time and ICU retention time of the observation groups were less than the control group (P <0.05). The time for procalcitonin (PCT) and white blood cell count (WBC) to return to normal of the observation groups was shorter than that of the control group (P <0.05). Conclusions Bronchoalveolar lavage during CPB surgery for CHD complicated with severe pneumonia is conducive to lung infection control, could ameliorate postoperative pulmonary function, reduce mechanical ventilation time and ICU retention time.